1. Field of the Invention
The present invention provides the pilot of an aircraft in the approach/landing environment with a cathode ray tube display that is the equivalent of the normal clear weather visual cues noted by the pilot in the said environment. The cathode ray tube is a member of a closed-circuit television system wholly contained within the aircraft. The video camera of this system possesses the unique feature of being not only supported for 5 (or 6.degree. of freedom but includes a "pinhole type" lens system to insure universal focus and adequate field of view of a miniature runway which is preferably illuminated by infrared, or near infrared light. The airborne self-contained closed-circuit system operates during a limited portion of the final approach to an instrument landing system (ILS) equipped runway of contemporary design (with added distance measuring equipment (DME)), or equally well with the proposed microwave landing system (MLS), or other compatible ground-based systems which define runway centerline and glide path information. The airborne self-contained system is accordingly an air-derived system which does not necessarily employ radar tracking or telemetering of ground and/or airborne devices. Furthermore, the system is devoid of complex electronic computer devices. This adds to its simplicity and reliability, which is very important to equipment of this type.
The video camera is supported on the miniature equivalent of a gantry crane so that the camera itself may be positioned with respect to the miniature landing runway in exact proportionate spatial dimensions that are taken by the aircraft itself in relation to the real runway upon which it is to land. Accordingly the pilot sees on the cathode ray tube display a black and white visual cue of the approach and landing comparable to that which he might observe during an actual twilight landing at the selected runway. It is a relatively simple matter for the aircraft flying under obscure visibility to be positioned, by aid of ground oscillators, on the final approach path to the runway after leaving the final approach fix. It is that part of the approach to landing and the landing itself (during which all aerodynamic parameters of the aircraft must change), namely the roundout and flare and touchdown which becomes a major burden on the pilot especially in the presence of turbulence and wind shears. This invention, accordingly, gives to the pilot the equivalent visual cues that he normally uses in a clear weather approach/landing. Meaningful normal visual cues are presented to the pilot which could tell the pilot to abort the landing and await better weather conditions at the runway.
2. Description of the Prior Art
Several attempts have been made to provide equivalent cues to the visual landing but none are complete and some fail by presenting unreal or distorted visual cues on the cathode ray tube. Other efforts parallel the simulator art and rely on radar tracking and the use of telemetering to transfer position of the aircraft being tracked to a ground simulator display after which this display is transmitted back to the aircraft for presentation on the cathode ray tube in front of the pilot.
U.S. Pat. No. 3,212,082, dated Oct. 12, 1965, entitled "Aircraft Approach and Landing System", issued to Donald W. Robinson, Jr. et at shows complex structure supporting camera means which involves a rotatable area of runways and in which an object of the invention states that it provides an approach and landing system in which ". . . the major portion of the system is ground-based, the airborne portion thereof comprising only a television receiver.' This is foreign to the instant invention. Furthermore, this patent discloses no means in which the rotation of the aircraft about its three axes, in addition to its position with respect to the runway, are combined to produce the visual cues of the instant invention. It is noted further that the airborne equipment of the patent to Robinson, et al ". . . includes a television screen 14 which may be fixed in the cockpit or which may if desired be rotatably supported for movement about a roll axis 16 extending longitudinally of the aircraft 18 and gyro-stabilized about said axis." The instant invention describes an airborne video camera with 6.degree. of freedom (or five as will be described) which reproduces the movements of the aircraft in space as well as its rotation about its own axes. Another marked difference between the instant invention and the patent issued to Robinson is the use in the instant invention of one runway which is not mounted on a turntable as in the referenced patent, which of course is unnecessary and only adds to the complexity of the mechanism.
Reference is now made to U.S. Pat. No. 3,383,679, dated May 14, 1968, entitled "Visual Landing Simulator for Instrument Flying," issued to Roger P. Baird, Jr. in which the abstract of disclosure definetly points out that the invention relates to ". . . a simulating device for Instrument Landing Systems of the type which utilizes airborne television receievers in connection with ground-based model airport, TV camera, TV transmitter, radar and simulating device, all for providing blind-flying pilots with simulated views of their airport." This patent as noted requires elaborate radar tracking, the transfer of this information from the radar to the ground-based model of the landing area, and subsequently the broadcasting of this information to an air-craft in flight, which is in great variance with the instant invention.
The patent to Baird shows means only for positioning the TV camera with respect to the landing area but does not rotate the camera about the three axes of rotation to which the aircraft is submitted during an approach/landing. In this patent to Baird it is noted that an ". . . airspeed indicator 34, and artificial horizon 33, mounted at top of pilot's instrument panel, in near view of my TV screen indicator to aid pilots in ease of seeing required information for making instrument approach and landings. " Indicates that roll and pitch information is separately displayed near the cathode ray tube or TV screen. Unless the TV camera is rotated in response to the pitch and roll and heading of the real airplane, a false picture of the approach/landing will be generated. Due to the fact that the TV camera is positioned at a substantially short finite distance to the landing model, a spurious picture will be presented that is not the equivalent of the pilot's view of the distant horizon (at infinity) as seen in flight.
Neither the patent to Baird nor the patent to Robinson show the horizon, ground, sky background as provided in the instant invention. Although Robinson shows a pictorial rendition of this, the horizon being fixed in the model will not produce the equivalent of the real world portrayal.
In U.S. Pat. No. 2,979,832, dated April 11, 1961, entitled "Visual Simulator for Flight Training Device." Issued to Wolfgang B. Klemperer, there is shown a gantry crane type of support for positioning a camera in vicinity of a model airport for later projection of the picture in a ground-base simulator. This patent therefore bears no relationship to the methods provided in the instant invention.